“Save Our Shells”: Bubbles Protocol 				
CLASS COPY-DO NOT WRITE ON

Background Information: Ischia Island
Watch the video clip about what is happening around Ischia Island: In your own words, please explain what is happening, what is causing it, what issues are caused by it and are the environmental implications of this phenomenon.
Central Question:
How does carbon dioxide affect salt water?
Overview of experiment:
Exhaling carbon dioxide into a beaker of salt water mimics the gas exchange that occurs between Earth’s atmosphere and oceans. You will track the resulting changes in ocean chemistry by monitoring changes in pH as you exhale into the salt water.
Introduction:
Remember: C=carbon, H=hydrogen, O=oxygen
When CO2 dissolves in seawater, the carbon and oxygen molecules bind together to form carbonic acid, which is shown in the following reaction: CO2 + H2O <----> H2CO3
This carbonic acid breaks apart in the water, releasing hydrogen ions and bicarbonate, shown here: H2CO3 <-----> H+ + HCO3-

					
			Acidic				  Neutral         Basic
Pre- lab questions:
What gas are you blowing into the water? 
What happens to the gas when you blow it into the water? 
How are you measuring change in the water during this lab? 
What does measuring the pH of the water tell us? 
After studying the reactions above, how do you think carbonic acid will affect the pH of salt water? 
Hypothesis:
If ___________________________________, then_______________________________________.

Materials:
o	100 ml saltwater
o	250 ml beaker
o	Straw
o	Timer
o	Universal indicator solution
o	
Role in Group	Student Name	
Timer		
Recorder		
Breather		
Materials		

Parafilm

Lab Procedure:
Preparation
1.	Assign a role to each group member 
2.	Familiarize yourself with the Universal Indicator Color Chart (p. 7). 
Trial
MATERIALS: Add 100 mL saltwater to a 250 ml beaker. 
MATERIALS: add 4 drops of universal indicator 
MATERIALS: Place a white sheet of paper under the beaker and record the initial color using the table on the data sheet. 
MATERIALS: Stretch the piece of parafilm to completely cover the top of the beaker – then insert the straw by poking a hole through the parafilm. 
RECORDER: Get the data sheet and prepare to record the color of the solution every 30 seconds, using the colors listed on the Universal Indicator Color Chart. 
TIMER: Get timer ready to record for TWO MINUTES - Begin timing AT THE SAME TIME as breather begins blowing. 
BREATHER: Begin blowing through the straw into the water at exactly the same time as the timer begins timing. Breathe at a steady rate, exhaling only through straw. (Be careful to not inhale or suck on the straw!)
TIMER: Call out 30 second intervals. 
RECORDER: As the timer calls out each 30 second interval, record the color at that time using the same color descriptions as the Universal Indicator Color Chart. 
BREATHER: Exhale/blow at steady breathing rate for two full minutes. 
RECORDER: Using the table on your data sheet and the Universal Indicator Color Chart, convert your color data to numbers, plot your data on the graph provided, and draw a line connecting the points to create a line graph. 

Data/ Results:
Known pH measurements:  Seawater = pH ~8.0  Tap water = pH ~7.0

Data Table:
Seawater	0 sec.	30 sec.	60 sec.	90 sec.	120 sec	
pH						
Color						

Graph:  plot IV on X axis, DV on Y axis

Universal Indicator Conversion Chart
Orangish Red	pH 2	
		
Reddish Orange	pH 3	
		
Orange	pH 4	
		
Orangish Yellow	pH 5	
		
Yellow	pH 6	
		
Greenish Yellow	pH 7	
		
Yellowish Green	pH 8	
		
Green	pH 9	
		
Bluish Green	pH 10	

Analysis and Discussion of data:
1.	As you blew through the straw, what were you adding to the water and how did that change the pH? 
2.	What did the universal indicator tell us about the water? 
3.	What does this tell us about the effects of carbonic acid in ocean water? 

Conclusion/Summary: (Revisit your hypothesis)

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“Save Our Shells”: Shells Protocol 				
CLASS COPY-DO NOT WRITE ON

Central Question:
How does a decrease in the pH of seawater affect the calcium carbonate shells of animals?
Overview of experiment:
Shelled organisms and organisms that create calcium carbonate skeletons are threatened by the drop in ocean pH (rise in ocean acidity) related to increased atmospheric carbon dioxide levels. Increasing acidity/lowered pH in ocean water not only causes the shells to dissolve, but it reduces the availability of carbonate ions – which animals use to build their shells and skeletons.
Ca 2++ CO3 2-   ->  CaCO3
Calcium + Carbonate -> Calcium Carbonate
You will observe the effect of an acidic environment on mussel shells through observations and measurements.
Pre- lab questions:
How do organisms make their shells? What are shells made of? 
What do you expect to happen to the shell in an acidic solution such as vinegar? 
What are sources of carbon dioxide and which of these sources are most likely to affect ocean pH? 

Hypothesis:
If ___________________________________, then_______________________________________.

Materials:
o	2 untreated shells
o	2 pre-treated shells (for the class)
o	100 ml vinegar
o	100 ml seawater
o	(2) 150 ml beakers
o	1 tweezer
o	Sharpie
o	Paper towels
o	Timer

Lab Procedure
MATERIALS: Remove your two untreated shells from their bags. 
MATERIALS: With a sharpie, label one shell “E’ for experimental and one shell “C” for control. 
RECORDER: Using your data table record your group’s initial observations of the control and experimental shell characteristics. 
MATERIALS: Find the mass of each of the shells. 
RECORDER: Record the starting masses of both shells on your data table. 
MEASURING: Pour 100 ml of vinegar into a 150 ml beaker and 100 ml of salt water into a second 150 ml beaker. 
TIMER: Set the timer for 30min. 
MATERIALS: At the same time: Add the untreated, control shell “C” shell to salt water and the untreated, experimental shell “E” to the beaker of vinegar and start the timer. 
RECORDER: In your data table, observe and record your group’s observations of what is happening to the shell while exposed to the vinegar over time. (at 0 minutes and 15 minutes) 
***EVERYONE: Between observations of your shell in acid (vinegar), spend time observing and recording observations of shell characteristics for the pre-treated (“Low Exposure” and “High Exposure”) shells.
MATERIALS: After 30min use the tweezers to remove the shell from the vinegar and place on a paper towel. Dry the shell with a paper towel as best as you can.
MEASURING: Find the mass of both the control and the experimental shells.
RECORDER: Record the final masses and observations of the experimental and control shells after treatment.
EVERYONE: Decide how to test the strength of the shell. Options are:
•	Test the shell strength by dropping the shell from a height of 5 feet from the ground and then record the damage or breakage on your data table 
•	Break the shell with text books to see how easily the shells break 

Data: Untreated Shells
		Control	Experimental	
Initial
(0 minutes)	Observations			
	Mass			
15 minutes	Observations			

Final
(30 minutes)	Observations			
	Mass			
	Damage/Breakage			
	
Pre-treated Shells
	Low Exposure	High Exposure	
Observations

Analysis and Discussion of Data:
1.	When you immersed the shells in vinegar how did you know that a reaction was happening? 
2.	How did observing the shells in vinegar relate to how animals are affected by a lower pH of ocean water? 
3.	How would shelled organisms be affected by a lower pH of ocean water? 
4.	What are the primary functions of shell for these animals? 
5.	Does it cost the animal energy to rebuild or repair their shell? Explain.

Conclusion/summary: (revisit hypothesis)
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